gcal_list_freebusy
AI agents call gcal_list_freebusy to retrieve information from Integrations MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves calendar availability data without modifying it. While it is a Read operation (no side effects), it accesses potentially sensitive personal scheduling information. Severity is medium because exposure of freebusy data could reveal sensitive timing patterns about user availability and activities, though it typically only returns free/busy blocks rather than event details.
From the tool's definition Tool name 'gcal_list_freebusy' indicates it retrieves free/busy status from Google Calendar. The 'list' prefix and absence of write/delete operations suggest read-only query functionality.
Attacks that exploit this kind of access
gcal_list_freebusy. It is categorised as a Read tool in the Integrations MCP MCP Server, which means it retrieves data without modifying state.
Register the Integrations MCP server in PolicyLayer and add a rule for gcal_list_freebusy: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Integrations MCP. Nothing to install.
gcal_list_freebusy is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the gcal_list_freebusy rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for gcal_list_freebusy. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
gcal_list_freebusy is provided by the Integrations MCP server (shriram-vasudevan/integrations-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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